ARCTIC VOL. 39, NO. 2 (JUNE 1986) P. 145-149 Characteristics of the Wolf (Canis lupus lubrudorius Goldman) in Northern Quebec and Labrador
G.R. PARKER’ and S. LUTTICH’
(Received 18 March 1985; accepted in revisedform 17 September 1985)
ABSTRACT. Two hundred and twelve wolves (Canis lupus labrudorius) shot by hunters in northern Quebec and Labrador during the winters of 1976-77 through 1983-84 were examined for various population parameters.An estimated annual adult survival rateof 55% and a recruitment rateof 49% suggest a population of moderate exploitation. The sex ratio did not differ significantly from 1:l. Fifty-five percent of yearling females were pregnant orin breeding condition. The average litter size allfor females was6.8. Internal fat deposits were greatestin young males and older females. Caribou (Rangifer tarandus caribou) was the most common food item found in stomachs. A sample of caribou bykilled wolves in the winter showed a selection for older-aged caribou with fat deposits slightly below ofthat the general population. Key words: wolf, caribou, northern Quebec, Labrador, predation
&SUMÉ. Un total de 212 loups (Canis lupus lobrudorius)Ws par des chasseurs dans le nord du Qubbecet au Labrador aucours deshivers de 1976-77 jusqu’i 1983-84furent examinbsah d’btablir divers param2tres relatifsi la population.Un taux de survivance annuelde 55% pour les adultes etun taux de recrutement de 49%suggerent une exploitation modbnk. Le taux de diffbrenciation sexuelle ne s’bloignaitguhre de 1: 1. Cinquante cinq pour centdes femelles âgks d’un an btaient enceintesou en condition aptei la reproduction.La portk moyenne btait de6.8. Les dbp6ts degraisse interne paraissaient en quantie maximale chez lesjeunes maes et les vieilles femelles. Le caribou (Rangifer tarandus caribou) btait la nourriture la plus communbment trouvk dans les estomacs. Un bchantillonnage de caribous tubs despar loups durant l’hiversignala la sblection de caribous plus âgbs avecdes dbp6ts de gras quelque peu infbrieurs i ceux de la population gbnbrale. Mots cl&: loup, caribou,nord du Qubbec, Labrador, activitbpddatrice Traduit pour le journal par Maurice Guibord.
INTRODUCTION quantified data in the literature describing any aspects of the ecology or population dynamics of the subspecies. The caribou (Rangifertarandus caribou)of northernQuebec and As part of the cooperative federal-provincial study of the Labrador,commonly referred to as the George River herd, George River caribou population, wolf carcasses were collected represent one of the largest O00 in 1984) and most rapidly (-600 by the Newfoundland-Labrador Wildlife Division from hunters expanding populations in NorthAmerica. Cooperative research invarious settlements withinthe range of thatpopulation. and management programs between Quebec and Newfoundland Canadian Wildlife Service was asked by the province of New- directed toward averting a populationdecline, i.e., increas- are foundland to examine the carcasses. This article reports on the ing annual harvests and reducing population growth.The George examination of 212 wolf specimens collected from within the River population has increased 100-fold over the past28 years range of the George River caribou populationduring the winters (only 5100 caribou were estimated in 1956 by Banfield and of 1976-77 through 1983-84. Eighty-one of those specimens Tener, 195 8). represented intact carcasses, the remainder skulls only. The factors contributing to natural control in the growth of Datawere also collectedfrom caribou killed by wolves. free-ranging caribou populations are complex andcontentious. Information relativeto the health of the caribou population is a Bergemd (1983) provided a summaryof the theories relativeto result of a collection of caribou in spring 1980 (Parker, 1981). numerical control of caribou populations.He suggested thatthe primary meansof control differs among biomes and that preda- METHODS tion is the most frequent and consistent means of population control in the boreal forestedregions of North America. Wolf specimenswere collectedfrom hunters of the communi- The most important predator of caribouother than man is the ties of Kuujjuaq and George River, Quebec, and Nain, Labra- wolf (Canis lupus). Although considerable attention has been dor. Most wolves wereshot by residents of those communities given to understandingthe population dynamics of the George while hunting caribou. Several were shot near settlements or River caribou population (Parker, 1981), the wolf of northern hunting camps. All specimens were frozen and transported to Quebecand Labrador (C. 1. labradorius) hasbeen largely Goose Bay, Labrador. To facilitate transport, external measure- ignored. By 1958 the wolf in northern Labrador had beenrare ments were taken of some prior to shipment (legs were then for 40-50 years (Bergerud, 1967). An increase in wolves was a removed and in thecase of males in 1982-83 and 1983-84 only natural and expected result ofthe increase in caribou numbers the skulls were shippedto Goose Bay for aging). and is consistent with the predationcontrol hypothesis presented Information on reproduction, diet and condition is from 136 by Bergerud (1983). However, as stated by Bergerud (1983), the wolves examined from1980-81 through 1983-84; 43 stomachs failure to date for wolves to halt the rapid expansion of that from that sample were examined for food items. Teeth from an population may disprove his predation limitation hypothesis. additional 76 skulls collected from 1976-77 through 1979-80 Other than referencesto the description and records of several were used for overall age structure analysis. specimensof C. 1. labradorius (Goldman, 1937; Anderson, Body weightis that ofthe skinned carcass. Total body length 1943; Young and Goldman, 1944; Harper, 1961), there are no was from tip of the nose alongthe dorsal side to base of the tail
‘Canadian Wildlife Service, Box 1590, Sackville, New Brunswick, Canada EOA 3CO ’NewfoundlandLabrador Wildlife Division, Goose Bay, Labrador, Canada AOP 1CO @The ArcticInstitute of North America 146 G.R. PARKER and S. LUTTICH
(tails weremissing from most carcasses). Two internal fat TABLE 1. Thesex and age structure of 212wolves collected in deposits were removed and weighed. They were: sternum, the northern Quebec and Labrador during the winters 1976-77 through pad of fat on the posterior end of the sternum; and, abdominal, 1983-84 the fat along the dorsal wall of the body cavity from the anterior end of the kidneys to the cavity formed by the pelvic girdle and Number of specimens vertebral column. Total fat weight was converted to a body fat FemaleMaleUnknown(yr) Age Total % of sample index to minimize bias from differential body weights. 21 0.5 20 63 104 49.1 fat index = fat weight (g) 1.5 15 10 28 53 25.0 6 8 6 8 2.5 6 20 9.4 carcass weight (kg) 3.5 2 19 2 15 9.0 The lower right canine tooth was removed. Teeth with open 4.5 2 3 1 6 2.8 root pulp canals were classified as pups. Teeth withclosed roots 5.5 2 1 1 4 1.9 weresawed inhalf at the gum line. The rootportion was 6.5 1 1 2 0.9 7.5 2 2 0.9 decalcified, and stained sections were mounted on slides. Sec- 8.5 tions were examined for cementum annuli. Ages were assigned 9.5 1 1 0.5 by adding 1.5 years to the number of annuli (Matson, 1981). A 10.5 1 1 0.5 second canine was removed from those specimens that had the Totals45 49 212 118 100.0 root foramen closed but showed no discernible annuli. These teeth were also severed in half at the gum line. Measurements weretaken of dentine thickness andmaximum pulp cavity TABLE 2. A composite life table (after Caughley and Birch, 1971) width. From a statistical analysis of those measurements it was from the age distribution of wolves collected in northem Quebec and determined that approximately one-half of those specimens with Labrador, 1976-77 through 1983-84 a closed root apical foramen, but no cementum annuli, were < 1 year old (see Parker and Maxwell, 1986 - this issue). Those f; d, wolves would have beencollected in late winter or early spring sizeSampleAge (yr) zf; %%. 1, (February-April). The remaining specimens were aged as 1.5 (x) (f;) (4)" (Idb (%Y years old. 0.5 104 0.49 1 .oo 0.49 Reproductive tracts were examined macroscopically for pla- 0.251.5 53 0.49 0.51 cental scars and embryos. Stomach contents were washed and 2.5 20 0.350.09 0.26 examined for food remains. Food items were separated, identi- 3.5 19 0.530.09 0.17 4.5 6 0.380.03 0.08 fied toindividual prey species, and weighed(wet weight) to the 5.5 4 0.400.02 0.05 nearest gram. 6.5 2 0.330.01 0.03 Marrow fat values from femurs of wolf-killed caribou were 7.5 + 4 0.02 0.02 1.oo determined by the dry-weight method (Neiland, 1970). "d, = probability at 0.5 yr of dying in age interval x, x + 1. "lx = probability at 0.5 yr of surviving to age x. 'q, = probability at age x of dying before age x + 1. RESULTS AND DISCUSSION Age Structure of 53%, slightly less than the average adult survival. The Seventy-four percent of the sample was aged at1.5 years old margin for error in these calculations is such that calculated or less (Table 1). Forty-nine percent of the sample was < 1 year mortality and rates of survival must be considered approximate old and only 7.5% was >4 years old. only and statements on population change (r), positive or nega- We used the Chapman-Robson method (in Eberhardt, 1969) tive, can be estimates only. for estimating survival and age-class compatibility. First year The representation of pups in winter in unexploited wolf survival (53%) was notcompatible with survival in the older age populations normally ranges from 13% (Kelsall, 1968) to 20% classes(x2 = 86.98;p<0.001;df = l).Asurvivalrateof55%for (Fuller and Novakowski, 1955) and in exploited populations the 1.5 year and older age classes was compatible with the from 35% (Pimlott et al., 1969) to 55% (Fuller, unpubl. data). assumption of a constant survival rate (x2 = 1.99; p>0.05; df = Statistics from this sample from northern Labrador and Quebec 1). A second test of compatibility compared observed and (i.e., 49% pups; 55% annual adult survival) suggest a popula- expected relative frequencies by age class assuming the calcu- tion of moderate exploitation (Mech, 1970). lated survival rate (i.e., 55%) was correct (Eberhardt, 1969). Sex Ratios The resulting x2 value of 3.95 with 5 degrees of freedom supported a survival rate of 55% for all adult (1.5 years and There was little variation from a 5050 sex ratio for all age older) age classes. classes (Table 1). The exception was the yearling class (1.5 years A composite life table was constructed (Table 2) showing the old) for which from a sample of only 25 the ma1e:female ratio age structure of the population with the usual assumptions was 7550. However, the overall ratio of the 94 specimens of relative to the dynamics ofthat population (e.g., unbiased known sex was5450. The slight bias toward malesfor the total sample, stable population, etc.). Following the approach by sample is typical of most wolf populations studied in North Mech (1970) and assuming a) an equal adult sex ratio, b) a America (Mech, 1970). In Finland, Pulliainen (1965) found that breeding rate for females 1.5 years and older of 60%, and c) a an extreme bias toward males wasassociated with the tendency mean litter size of 6.8, young wolves experience a first-year for males to immigrate into unoccupied range; sex ratios survival of 55%, identical to survival of older age classes. approach equality on established breeding range. We conclude Earlier tests of age class compatibility found first year survival that the wolves in the sample from northern Quebec and NORTHERN QUEBEC AND LABRADOR WOLVES
Labrador represented established breeding populations with sex ratios approaching 1: 1. Reproduction Thirty-four female reproductive tracts wereexamined for evidence of embryos or placental scars. Twelvewere from females < 1 year old; all were small and showed no evidence of precocial breeding. Of 10 females aged1.5 years, 4 tracts were similar to those of pups, one was pregnant with 9 embryos5 and had enlarged uteri. The latter were presumed to be in early stages of pregnancy or in breeding condition. All 12 uteri from females 2.5 years or older were enlarged. Sevencontained either embryos or scars from previouspregnancies. Scars were not apparent in5 of the 12 tracts. The mean number ofscars and embryos was 6.8 (s.d. = 2.2; range = 4-10). This samplesuggests a breeding rate of 60% for yearlings (22 months). In Alaska, Rausch (1967) reported that ovulation by Id pups (8 months old) was extremely rare and that first breeding normally occurred at 22 months. Otherreferences also suggest that breeding first occurs in the second year for captive wolves (Murie,1944; Young and Goldman, 1944; Garceau, 1961; Pulliainen, 1965). Mech (1970) compiled averagelitter sizes for wolves in NorthAmerica and Finland, and those averages ranged froma low of 2.8 in Finland(Pulliainen, 1965) to 6.5 in Alaska (Rausch,1967), less than the average of 6.8 in thisstudy. Body Size and Condition Maleand female wolves reached adult bodyweight and length toward the end of their second year (Fig. la). Due to a large variance in weights for the 1.5 year class, differences between means for those two age classes were not significant. 0.5 1.5 2.5 3.5+ 0.5 1.5 2.5 3.5+ Differencesbetween meansfor the 0.5 and 2.5 year classes were AGE CLASS (YR) significantfor both males(t = 5.43; p<0.005) and females(t = FIG. I. Mean body measurementsof wolf carcasses collected in northern Quebec 2.14; pc0.05). Although female weights were slightly higher and Labrador, 1980-81 through 1983-84: (a) carcass weight, (b) carcass length than males for the 0.5 year class, male weights were higherfor (to base of tail), (c) sternum fat index, (d) abdominal fat index. the older classes (between sex differences not significant). Wolves also reached adult body length by the end of their second year (Fig. lb); differences in lengths between the first Winter Diet twoageclassesweresignificantformales(t = 2.65;p
Wolf-Killed Caribou However, a comparison of the age structure of wolf-killed caribou for the same three ageclasses between the two regions Sex und age structure.During late winter aerialsurveys of the gaveadifferentresult (x2 = 60.5;p<0.001; df = 4). Innorthern George River caribou population in 1981-82 and 1982-83, 59 Manitoba, Miller (1975) foundonly 6.8% of a wolf-killed caribou presumably killed by wolves werefound. The ages of sample 28yeqs old, while in Quebec-Labrador that ageclass 49 of them were determined by tooth eruption for calves (0.5 represented 37.2% of the sample. The proportions of calves in year) and yearlings(1.5 years) and a count of tooth cementum this study and that by Miller (1975) were 1 1.6% and 18.0% annuli for those caribou 2.5 years and older. Sex was deter- respectively (x2 = 0.94;p>0.05; df = 1). Differences inrepre- mined for 45 of the carcasses. sentation of caribou 1-7 years old in the wolf-killed samples In April 1980, 159 caribou were collected from the spring between the twostudies was notsignificant (x2 = 3.28;p>0.05; migration of the George River population nearNain, Labrador df = 1). (Parker, 1981). The 1980 collection was considered a random The male:female ratio of the wolf-killed sample was 5750. sample of the age structure of the adultfemale-juvenile compo- By age group the sex ratio was: 0.5-3.5 years = 7550; 4.5-8.5 nent of the population. Although caribou carcasses were col- years = 6450; 9.5-14.5 years = 5050. The sex ratio favouring lectedthroughout the wintering range of the George River males in the youngercohorts reached equality for theolder age population, the representationof age classes in the 1980 sample classes. is used here as the expected age structure within the sample of Physical condition. The percentage fat in femur marrow was wolf-killed caribou. determined for 29 wolf-killed caribou. The percentage marrow AChi-square analysis showedthat caribou 28.5 yearsold were fat values by caribou age class were: 0-1 year - 77.2%; 1-2 = overrepresented in the wolf-killedsample (x2 17.50;p
CONCLUSIONS Population In the past 15 years, the George River caribou populationof northern Quebec and Labrador has experienced a rapid expan- sion in total numbers and homerange. The situation represents an anomaly relative to thepredation limitation hypothesis (Bergerud, 1983). Wolfdensities have not yet attained the capability of reducing recruitment below the rate of annual mortality. This study shows that the productivity of wolves within the range of the George River caribou is high. Over one-half of females breed in their second year andthe number of young per litter is high. Although statistics suggest that wolves in northern Quebec and Labradorrepresent a population of moderate exploi- tation, the high rate of productivity should ensure population growth. Although the representation calvesof in the wolf-killed sample of caribou was notsignificantly different from that in the population, calves maybe underrepresented in the sample because of their small size, greater use by wolves and subse- quent rapid obliteration fromview. Wolf-killed caribou in this study were Fust observed fromaircraft; many had been deadfor a considerable time. Representation of old caribou(28 years), however, is signifi- cantly greater than in the 1980 spring sample and the wolf-killed sample from the Kaminuriak population. These data suggest 1 2 3 4 5 6 7 8 91011 12131415 thatwolves within the range of theGeorge River caribou AGE CLASS (YR) population are selecting for older caribou and killing calves at least in proportion to, andprobably higher than, their FIG.2. Distribution of GeorgeRiver caribou by age class within a sample collected in spring 1980 (population) and withina sample ofwolf-killed caribou availability. collected in the late winters of 1981-82 and 1982-83. As wolf densities increase in response to increasing prey NORTHERN QUEBEC AND LABRADOR WOLVES 149
availability, selection for calves may also increase. A switch REFERENCES from older caribou to calves commensurate with increasing ANDERSON,R.M. 1943. Summary ofthe large wolves of Canada, with caribou and wolf densities agrees with Bergerud’s predation description ofthree new arctic races. Journalof Mammalogy24(3):386-393. control hypothesis. BANFIELD, A.W.F., and TENER, J.S. 1958. A preliminary study of the The calving grounds for most northern mainland caribou Ungava caribou. Journal of Mammalogy34(4):561-573. populations, especially the George River population, are not BERGERUD, A.T. 1%7. Management of Labrador caribou. Journalof Wild- prime wolf denning habitat. This may explain why such areas life Management31(4):621-642. -. 1983. The natural population control of caribou. In: Bunnell, F.L., have been selected for calving by northern mainland caribou Eastman, D.S., and Peek, J.M., eds. Symposium on Natural Regulationof populations. The prime denning areas for northern wolves is Wildlife Populations. University of Idaho Forestry, Wildlife and Range near the treeline. It is at the treeline that wolves are without Experimental Station Proceedings No. 14. 14-61. caribou for the shortest period of time. As wolf populations CAUGHLEY, G., and BIRCH, L.C. 1971. Rateof increase. Journal of Wildlife Management35(4):658-663. increase, more subadult (non-breeding) wolves may followthe EBERHARDT,L.L. 1969. Populationanalysis. In: Wildlifemanagement migrating caribou farther onto the tundra toward the calving techniques. Giles, Jr., R.H., ed. Washington, D.C.: The Wildlife Society. grounds. More wolves on the calving area would mean more 457-495. predation upon young calves (Miller and Broughton, 1974). FULLER, W.A., and NOVAKOWSKI, N.S. 1955. Wolf control operations, An increase in wolves and increased predator-preycontact at Wood Buffalo NationalPark, 1951-1952.Canadian WildlifeService, Wild- life Management Bulletin Series1, No. 11. 20 p. all seasons would increase predation upon caribou< 1 year old. GARCEAU, P. 1%1. Wolf predation studies on black-tailed deer. Alaska This scenario agrees with the predation limitation hypothesis. Department of Fish and Game. FederalAid, Alaska, W-6-R-3, Work Plan K, However, with a carbiou population now approaching600 OOO Job No. 3. 16 p. animals and estimated rates of recruitment far exceeding esti- GOLDMAN, E.A. 1937. The wolves of North America. Journal of Mammal- ogy 18(1):3745. mated mortality, it seems unlikely that wolves alone will be HARPER, F. 1961. Land and fresh-water mammals of the Ungava Peninsula. responsible for terminationof population growth. As both University of Kansas. Miscellaneous Publication No.27. 178 p. provinces are now considering commercial harvesting of cari- KELSALL, J.P. 1%8. TheMigratory Barren-Ground Caribou in Canada. bou, thus substantially increasing mortality inflicted by man, CanadianWildlife Service Monograph No. 3. Ottawa:Queen’s Printer. 340 p. the combined increased predation by man and wolf may succeedKUYT, E. 1972. Foodhabits of wolves on barren-groundcaribou range. in controlling the growth of the George River population. Canadian Wildlife Service Report Series No.21. 36 p. Unchecked growth of caribou populations on islands with no MATSON,G.M. 1981. Workbookforcementwnanalysis.Matson’sMilltown, predation by wolves or man leads to range deterioration and Montana. 30 p. swift reductions in population size through depletion of avail- MECH, L.D. 1970. The Wolf the Ecology and Behavior of an Endangered Species. Garden City, New York The Natural HistoryPress. 384 p. able forage. This control of caribou numbers by the “food MILLER, D.R. 1975. Observations ofwolf predation on barren ground caribou limitation hypothesis” has not been observed in free-ranging in winter. In: Luick, J.R., Lent, P.C., Klein, D.R., and White, R.G., eds. “continental populations. ” Proceedings, First International Reindeer and Caribou Symposium. Biologi- The GeorgeRiver situation represents a unique opportunityto cal Papers of the University of Alaska. Special Report No. 1. 209-220. MILLER, F.L. 1974. Biology of the Kaminuriak Population of Barren-Ground monitor the response of an expanding caribou population to Caribou. Part 2. Dentition as an indicatorof age and sex; composition and increased predation by wolves and man. socialization of the population. Canadian Wildlife Service Report Service No. 31. 88 p. -and BROUGHTON, E. 1974. Calf mortalityon the calving groundof Kaminuriak caribou during 1970. Canadian Wildlife Service Report Series No. 26. 26 p. MURIE, A. 1944. The Wolves of Mount McKinley. United States National Park Service Fauna SeriesNo. 5. 238 p. ACKNOWLEDGEMENTS NEILAND, K.A. 1970. Weight of dried marrow as indicator of fat in caribou femurs. Journal of Wildlife Management34(4):904-907. This study was made possible through the cooperation of the huntersPARKER, G.R. 1981. Physical and reproductive characteristicsof an expand- of northern Quebec and Labrador. We thank Maria Berger for her ing woodland caribou population (Rungifer rurundus caribou) in northern assistance in the analysis of wolf specimen material at Goose Bay, Labrador. Canadian Journal of Zoology59(10):1929-1940. Labrador, and for the examination of wolf-killed caribou in the field. -and MAXWELL, J.W. 1986. Identification of Pups and Yearling John Maxwell, Canadian Wildlife Service, also assistedin the analysis Wolves by Dentine Width in theCanine. Arctic 39(2): 180-181. of material, especially the histological sectioning of wolf teeth. SandyPIMLO’IT, D.H., SHANNON, J.A., and KOLENOSKY, G.B. 1969. The Gordon, Quebec Department of Tourism, Fish and Game, and Williamecology of thetimber wolf in Algonquin Park.Ontario Department of Lands Anderson, former Wildlife Enforcement andProtection Officer, Nain, and Forests Research Report (Wildlife) No.87.92 p. Labrador, assistedin the collection of specimen material. Johnny May,PULLIAINEN, E. 1%5. Studies ofthe wolf (Canis lupus L.) in Finland. Annales Zoologici Fennici2:215-259. pilot, also collected andtransported wolf carcasses. Funding forthis RAUSCH, R.A. 1967. Some aspects of the population ecology of wolves, study came from the CanadaNewfoundland-CoastalAgreement, the Alaska. American Zoologist7:253-265. Interim Coastal Labrador Agreement and the Newfoundland-Labrador YOUNG, S.P., and GOLDMAN, E.A. 1944. The Wolves of North America. Wildlife Division and the Canadian Wildlife Service. Parts 1 and 2. Washington, D.C.: American Wildlife Institute. 636 p.